six new Golden Comets, sleeping habits

We just brought home our first chickens, six Golden Comets, we have a 6x6x6 fenced in area off from a 6x8x8 hen house. We placed a roost 15inces off the floor 8ft long made from a 2x4 with wide side flat. Only one uses it, 3 pile onto a small high spot by the windows, and two squish together in a nesting box. This puts six in one corner and one by herself. We didn't see thing coming. We thought they would love their roost. The hen using the roost it is at the furthest distance from the rest. Could this be a pecking order taking place. Does it matter to them who is highest? Maybe they all hate this one hen? During the day, I don't witness it. I do notice that there is one that is a bit of a loner, but nothing that is continuous,